Event Title

Presenter Information

Faculty Advisor

Swarna Basu

Start Date

25-4-2017 12:00 PM

End Date

25-4-2017 1:00 PM

Description

The ability of three different porphyrins to interact with four different quadruplex DNA sequences, 15mer, 22mer, mixed G1, and mixed G2, via intercalation and π-π stacking was determined using UV-Vis and fluorescence spectroscopy. A water-soluble porphyrin was synthesized by functionalization of tetrakis-(perfluorophenyl) porphyrin (TFPP) with copper (II) chloride, followed by PEGylation. Its interaction with various DNA sequences (duplex, quadruplex and mixed) in the presence of cations was studied via systematic spectroscopic titrations. A red shift in the Soret band of the UV-Vis spectra of meso-5,10,15,20-tetrakis-(N-methyl-4-pyridyl) porphine (TMPyP4) as well as peak sharpening and intensity decrease in fluorescence spectra revealed strong interactions with all four annealed DNA sequences. No apparent preference between sequences with TMPyP4 could be determined based on the spectra. Binding was diminished in the Cu2+ derivative of TMPyP4, with no evidence of binding to 15mer. The modified Cu2+ derivative of TFPP failed to interact with any of the four sequences. It is unclear whether this failure is a consequence of structural modifications, the presence of Cu2+, or the structure of TFPP itself.

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Apr 25th, 12:00 PMApr 25th, 1:00 PM

Interaction of a water-soluble porphyrin with various DNA sequence: A spectroscopic study

The ability of three different porphyrins to interact with four different quadruplex DNA sequences, 15mer, 22mer, mixed G1, and mixed G2, via intercalation and π-π stacking was determined using UV-Vis and fluorescence spectroscopy. A water-soluble porphyrin was synthesized by functionalization of tetrakis-(perfluorophenyl) porphyrin (TFPP) with copper (II) chloride, followed by PEGylation. Its interaction with various DNA sequences (duplex, quadruplex and mixed) in the presence of cations was studied via systematic spectroscopic titrations. A red shift in the Soret band of the UV-Vis spectra of meso-5,10,15,20-tetrakis-(N-methyl-4-pyridyl) porphine (TMPyP4) as well as peak sharpening and intensity decrease in fluorescence spectra revealed strong interactions with all four annealed DNA sequences. No apparent preference between sequences with TMPyP4 could be determined based on the spectra. Binding was diminished in the Cu2+ derivative of TMPyP4, with no evidence of binding to 15mer. The modified Cu2+ derivative of TFPP failed to interact with any of the four sequences. It is unclear whether this failure is a consequence of structural modifications, the presence of Cu2+, or the structure of TFPP itself.